Ludwig van Beethoven's only opera, Fidelio (1814) tells of a young wife, Leonore, who disguises herself as a male servant, Fidelio, in order to rescue her husband Florestan from imprisonment. He has been detained for exposing the crimes of the nobleman Pizarro, and is starving in prison. Beethoven found the creation of the opera extremely challenging, but although it is rarely performed today it found critical success.
Working with the prison guard Rocco, Leonore arranges to speak to Florestan. However, Pizarro learns that a minister is on his way to investigate accusations against him, and decides to kill Florestan rather than have the minister discover him. Hiding in the room, Leonore intercedes before he commits the murder and reveals herself just as the minister arrives. The leads and townsfolk sing 'Heil sei dem Tag! (Hail to the Day!)', a song of praise to justice and freedom from tyranny, and praise Leonore for rescuing Florestan. Throughout the opera, the imminent arrival of the minister suggests that there is a greater good which must eventually bring Pizarro to judgement.